Caproic acid, responsible for the odor of dirty socks, is composed of C, H, and O atoms. Combustion of a 0.225-g sample of this compound produces 0.512 g CO2 and 0.209 g H2O. (a)What is the empirical formula of caproic acid? (b) Caproic acid has a molar mass of 116 g/mol. What is its molecular formula?

  Empirical formula = C3H6O

C6H1202---Molecular formula

Explanation:

we first find the masses of C, H  and O contained in the sample

mass of carbon

Mass of CO2 = 0.512g

molar mass of carbon =  12g/mol

Molar mass CO2 =  12+ (16X2)=44g/mol

Mass C = 12/44x 0.512 = 0.1396g  of carbon

Mass Hydrogen  

mass of H2O= 0.209g

Molar mass H2O = 18g/mol

Molar mass Hydrogen  = 1.0079g  x 2 = 2.0158g since  Hydrogen gas is diatomic

Mass H = 2.0158/18 X 0.209 = 0.0234g Hydrogen

Mass of Oxygen in the sample  =  overall mass of Sample - mass of hydrogen and oxgen=

0.225 - ( 0.1396 + 0.0234) = 0.062g Oxygen

A) T o find Empirical formula

1ST STEP-- Divide through by each  relative  atomic mass:

C = 0.1396/12 = 0.01163

H = 0.0234/1.0079 = 0.0232

O = 0.0619/16 = 0.00387

2nd step  Divide  by smallest answer

C = 0.01163/0.00387 = 2.0998 = 3

H = 0.0232/0.00387 = 5.99 = 6

O = 0.00387/0.00387=1

Empirical formula = C3H6O

B)To find molecular formula

Given that  molar mass of caproic acid as 116g,

we will use our empirical formulae to find molecular formulae with the equation

(C3H6O)n= 116g/mol

12x3 + 1x6 + 1 x16= 58g/mol

58n= 116g/mol

n = 116/58= 2  

= (C3H6O)2= C(3X2) H(6X2) O(1X2)

C6H1202--- MOLECULAR FORMULA

every chemical equation adheres to the law of conservation of mass, which states that matter cannot be created or destroyed. therefore, there must be the same number of atoms of each element on each side of a chemical equation.